The man attended A&E just after 4pm on Wednesday with abdominal pain, and was triaged at 5.30pm.
Photograph: Chris Radburn/PA

An 85-year-old man died while waiting in a hospital’s accident and emergency unit because of the “dangerous overcrowding of the department”, according to a leaked internal email.

Northampton general hospital NHS trust’s medical director, Matthew Metcalfe, said in the email, leaked to the Health Service Journal (HSJ), that the patient attended A&E complaining of abdominal pain on Wednesday afternoon.

The man was seen and assessed within 90 minutes and was waiting on a chair to be seen by senior staff after a blood test suggested he may have heart problems, the HSJ reported. His condition deteriorated just before 1am and he suffered a cardiac arrest.

Metcalfe’s email said: “Last night a patient died due entirely to the dangerous overcrowding of the department. The risk we have all been aware of, but may have felt hypothetical, has just happened.”

A spokeswoman for the trust said Metcalfe sent the email to consultants “to ensure they were fully aware of the seriousness of the position in our emergency department and also the importance of their ongoing support to our patients attending the department and their colleagues in the ED [emergency department] team”.

The trust said in a statement: “Ideally this patient would not have waited so long, would have been reviewed sooner by a senior consultant and might have been in a hospital bed on a ward at the time of his deterioration. We don’t yet know what difference this would have made to the final outcome.”

The hospital’s A&E unit has seen an average of 400 patients a day attending in recent months, an increase of almost 30% on the same period last year.

“This has inevitably had an impact on our ability to consistently provide a high standard of patient safety in our ED,” the trust said.

It said staff in the emergency department made every effort to see, assess and treat patients. “However, in this situation the long wait for further treatment and assessment led to an unacceptable outcome.”

The trust said it had apologised to the man’s family and would carry out a full investigation “to ensure any learning from this sad incident is taken forward”.